In many practical situations, it is desirable to have a light source that can produce omnidirectional light emission. As an example, this light source is a ceiling lamp for illuminating the floor under this lamp. For practical consideration, it is used herein that omnidirectional light emission refers to light emission where the cone of the emitted light extends over at least half of the sphere.
Incandescent lamps have been commonly used for omnidirectional light emission. There is a trend to replace incandescent lamps with light emitting diode (LED) lamps. To provide sufficient illumination, the LED lamps are usually of high power. Efficient dissipation of heat generated by LEDs in these lamps is of paramount importance.
In US20130070458, a LED bulb supporting omnidirectional light emission with a heat-dissipating arrangement is disclosed. The LED bulb has a heat-dissipating device comprising a base, and a plurality of heat dissipating bodies installed on the base. Each of the heat dissipating bodies has a V-shaped cross section, and is fixed with a LED light source module. The heat dissipating bodies are circumferentially arranged to produce omnidirectional light. A certain space is left between adjacent two heat dissipating bodies to form an air ventilation channel for heat dissipation. However, a direct flow of air is realizable only in the horizontal direction but not in the vertical direction when the LED bulb is held upright in the vertical direction, leading to reduced heat dissipation capability.
There is a need in the art to have a lighting device that provides omnidirectional light emission and achieve improved heat dissipation capability over the one disclosed in US20130070458.